Walls and Roof

The Taft School Residence has a durable, very insulated thermal envelope to create an air-tight, bridge-free space.

Subslab assembly

R-28 under slab

Subslab R-value 28.0
Slab edge assembly

R-20 at slab edge

Slab edge R-value 20.0
Foundation wall assembly

Inside the solid concrete foundation is 3” closed cell foam behind 2x4 stud walls and cellulose in the cavity.

Foundation wall R-value 32.0
Above grade wall assembly

Double stud walls have 2¼” closed cell foam plus 8½” dense pack cellulose for a R-49 cavity. The exterior sheathing is R-6.6 Zip Wall System with taped seams to create the continuous air barrier.

Above grade wall R-value 55.0
Flat attic assembly

The attic floor is framed with I joists and serves as the top of the building's air-tight envelope, for it has 24" to 36" of blown denspak cellulose insulation both on top and below the floor. The center of the attic floor is double framed with perpendicular boards, so that the HVAC equipment can be between the ceiling and distribution systems and remain in the envelope.

Flat attic R-value 86.0

Windows and Doors

Window Assembly:

The windows are made of European Eco-clad & uPVC frames are triple glazed with argon filling and two low-E coatings that have a U-value of 0.11. All rough areas around windows are taped to prevent air leakage.

Door Assembly:

Similar to the windows, all exterior doors are made of European Eco-clad & uPVC frames are triple glazed with argon filling and two low-E coatings that have a U-value of 0.11. All rough areas around windows are taped to prevent air leakage.

Average window U-factor 0.11
Door U-Factor 0.11

Mechanical Systems

Space cooling - Manufacturer & Model Mitsubishi MXZ0B Multi Split Heat Pump
Space heating - Manufacturer & Model Mitsubishi MXZ0B Multi Split Heat Pump
Domestic hot water - Manufacturer & Model Stiebel Eltron Accelera 300; 2.73 EF
Ventilation - Manufacturer & Model Zehnder Novus 300
Lighting Manufacturer and Model
Lighting Efficiency
Mechanical Equipment Installation Details and Comments

Partially ducted air-source heat pumps provide efficient heating and cooling while a heat-pump water heater with occupancy sensors in the baths delivers immediate hot water.